Wastewater surveillance strategy as an early warning system for detecting cryptic spread of pandemic viruses

Infectious disease surveillance is a crucial part of public health and essential for detecting and stopping disease epidemics. Surveillance systems for infectious diseases are primarily event-based, meaning they are meant to identify increases in either the number of cases caused by the pathogen confirmed by laboratory testing or the number of cases where individuals present a specific constellation of symptoms (syndromic surveillance). Additionally, incorporating novel pathogens into current event-based monitoring networks is challenging. Wastewater-based epidemiology (WBE) is based on the idea that pathogens excreted in bodily fluids that enter the sewage system can be found, aiming for early detection of cases and outbreaks, especially when traditional epidemiological approaches are limited. The wastewater system is merely one component of the environment that needs attention.1 The genomic investigations about severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), monkeypox (Mpox) virus and poliovirus, causing outbreaks during the last year, revealed an early cryptic spread. Strikingly, detecting these three viruses in wastewater shows that wastewater surveillance can be used as a proactive strategy for viral pandemics and a tool for detecting the silent spread of pandemic viruses before pandemics exist.2–4 Wastewater contains many infectious disease organisms, and to gauge the state of a community’s health, a representative sample should be gathered and studied, and wastewater is ideal for this purpose (Figure 1). The geographic range of transmission of emerging diseases can be shown through wastewater surveillance, validating the absence or low risk of transmission and warning of an increase in transmission.5 Continued studies are required to determine the broad applicability of wastewater monitoring for infectious illnesses, given the cheap cost and population-level representation that a single wastewater sample offers. Poliovirus, measles virus, enteroviruses, hepatitis A and E viruses, Ebola virus, noroviruses, influenza A virus, dengue virus, Mpox virus and SARS-CoV-2 have all shown the effectiveness of WBE as indicators of pathogen infection and prevalence in the community. Wastewater-based epidemiology shows a promising role as an ideal source for the identification of viral threats during their cryptic spread before the commencement of pandemics. Moreover, wastewater genomic surveillance at the building level describes the structure and dynamics of community viral transmission and can pinpoint transmission pathways. When paired with rapid sequencing technology, it can be utilized in real-time to more precisely direct public health actions. This high-resolution method is especially helpful in settings where many people congregate or pass through, like schools and airports, and in which many people are vulnerable, like nursing homes and hospitals, where it is necessary to monitor the environment in order to direct public health interventions.6 Infected animals and people secrete infectious substances through their secretions, like feces and urine. Monitoring sewage pathogens in animal habitats where there is a lot of human activity can reveal early warning signals and improve the traceability of infectious diseases, which could hasten the reduction of risks to public health posed by zoonotic pathogens. For the prevention of future pandemics and a prompt and effective reaction to them, wastewater pathogen surveillance under the One Health framework is crucial; therefore, WBE is especially crucial for identifying early warning signs and tracing the origin of emerging and re-emerging diseases in livestock farms and wet markets.7 The daily wastewater sample measurements and the clinical data are highly correlated.8 However, depending on genomic wastewater surveillance alone could be a risky mistake (Table 1); contrarily, it will give valuable information in tandem with clinical genomic surveillance and other detection methods. Employing wastewater surveillance to keep a close eye on populations for pandemic viruses has some difficulties. The methodology for sampling, sample pretreatment, viral concentration, molecular techniques, detection and interpretation of obtained results need for developing standardized global guidelines. Each virus has unique properties; hence the best methodology among the ones already in use must be chosen,4 and there are still some factors affecting the methodology like virus concentration, the effect of seasonal variability of wastewater under investigation.9 Challenges of WBE and proposed solutions Very low (e.g. flow dilution) Degraded Enrichment through RNA concentration methods and for PCR inhibitors Refrigerated sampling system (for inhibiting damaging enzymes, such as RNAses) Efficient sample processing and sensitive detection Additional data and statistical models can be used, and validation of model outputs using reliable estimates of prevalence Improving viral concentration methods (higher sequencing depth, bioinformatics tools and long reads) Untargeted metagenomics and metatranscriptomic shotgun sequencing approaches can be used to identify any circulating microbial DNA or RNA Additional data and statistical models can be used Untargeted metagenomics and metatranscriptomic shotgun sequencing approaches can be used to identify any circulating microbial DNA or RNA A better understanding of the amount and the duration of virus shedding via feces (dynamics of viral shedding) Long-term monitoring needed to obtain trustworthy data and to conduct the correlation with clinical testing A shared platform that brings together multiple data sources to overcome the gaps and biases in any one source Sampling from different locations Such as the tolerable duration of the SARS-CoV-2 virus is about 100 and 20 h in winter and summer Consideration of the variability of wastewater parameters (e.g. seasonality temperature variations) and the occurrence of extreme weather events Establishing standardized protocols to ensure the comparability of wastewater studies and eliminate biased results Provision of funding through governmental, non-governmental and other resources Reforming and establishing governance and legislative frameworks Investment in wastewater infrastructure Similar methods can be used to study samples from surface waters and point sources, although additional considerations of topography, water pooling and flow are needed to maximize catchment size Sequencing workflows reconfigured in accordance with available instruments, reagents, funding and facilities e.g. portable low-throughput sequencers Cooperation between the governmental, academic and private sectors Sufficient budget to support the necessary equipment, testing supplies and personnel Researcher expertise Community engagement (public knowledge and acceptance) Sound economic status Continued cooperation in sharing of the research labs’ deep expertise with their public and commercial partners Building and maintaining trust via communication about the goals of wastewater surveillance from local leaders and experts and co-design with community members The main stakeholders, such as public health organizations and labs, must have a strong commitment to and level of cooperation for utilizing and implementing wastewater monitoring and sequencing LMICs, low- and middle-income countries; WBE, wastewater-based epidemiology; WW, wastewater. Since asymptomatic and moderate cases are inevitably underrepresented in the group of verified cases, detection in wastewater may serve as an objective diagnostic. Such a study will allow researchers to learn more about the effectiveness of wastewater-based surveillance, particularly as an early warning system for viruses like Mpox.2,4 Wastewater surveillance could extend as a powerful platform for detecting emerging and re-emerging viruses and antimicrobial resistance genes or drugs. Nevertheless, genetic surveillance in wastewater is technically difficult. Poor sequencing coverage is a consequence of low virus loads, highly fragmented RNA and elevated levels of PCR inhibitors in complicated environmental samples.10 Wastewater-based monitoring has been broadly deployed for surveillance of antibiotic resistance genes, xenobiotic and human biomarkers and anthropogenic drugs. Now, we can believe in the results coming from wastewater surveillance as an alert to imminent public health concerns with quick preparedness and proactive prevention control plans to be formulated and the ability to put it out early before the virus affects the community. The national-scale WBE has proved to promote public health through its accuracy and information richness, and many developed nations have established national and regional WBE systems, such as USA and UK. WBE holds particular potential for nations lacking intensive individual monitoring and its potential for enhanced worldwide surveillance of other infectious diseases in the future.11 It is imperative to exchange knowledge from various surveillance programs, and building wastewater surveillance infrastructure requires to be increased and sustained investment. It is important to think about wastewater monitoring as a possible strategy for many infectious illnesses and future pandemic threats. The inclusion of other indicators of virus dissemination at the community level, such as illness incidence and hospitalizations, might enhance wastewater surveillance investigations.12 AbdulRahman A. Saied (Conceptualization [lead], Data curation [lead], Investigation [lead], Visualization [lead], Writing—original draft [equal], Writing—review & editing [equal]), Asmaa A. Metwally (Writing—original draft [equal], Writing—review & editing [equal]), Manish Dhawan (Writing—original draft [equal], Writing—review & editing [equal]), Deepak Chandran (Data curation [supporting], Investigation [supporting], Writing—original draft [equal], Writing—review & editing [equal]), Chiranjib Chakraborty (Data curation [supporting], Investigation [supporting], Writing—original draft [supporting], Writing—review & editing [supporting]), and Kuldeep Dhama (Data curation [supporting], Investigation [supporting], Writing—original draft [equal], Writing—review & editing [equal]) None declared. None declared.